I feel ya. The A-10 has so many fans (and for good reason), that it's nigh impossible for anyone to believe it's obsolete. But you're right, and you're perhaps being unfairly downvoted.

There's a great article here breaking this down:
https://baloogancampaign.com/2015/02/02/10-future-us-close-a...

To summarize:
- The A-10 was designed for an era when SAMs weren't as sophisticated as they are today. The GAU-8 cannon was to be an affordable weapon for eliminating tanks, but even as it was entering service it was soon clear that modern systems were outranging the cannon, and the Maverick soon became the primary anti-armor weapon of the A-10 due to it's standoff range. (source: colleague who was an A-10 test pilot (in the only two-seater made no less!) and links I can't find now)

- This proved true in Iraq (see link above) where the A-10 was getting shot up quite a bit against frontline units, and F-16s with their higher speed were sent in instead. It's a good reminder here that again, the cannon is no longer the primary weapon against armor in a high-threat environment. When that's taken into account, the A-10 and F-16 have similar weapons capabilities.

- The A-10s primary advantage in a low-threat environment is it's high endurance time. Here, it's being squeeze from two sides: Low-cost COIN aircraft like the A-29 Super Tucano, and high altitude bombers with targeting pods like the B-52. (https://www.youtube.com/watch?v=vw2qPzl1gtM). The A-29 is very effective in the counterinsurgency role for a fraction of the cost where it's not running against sophisticated AA systems. On the other end, you have the B-52, loitering at 35,000+ with an enormous load of munitions that can be called down on command and well above the range of man-portable systems.

- Check this video here of the late John McCain and a hearing with the Air Force. I've FFed the time to the general's answer to him. McCain, experienced as he was, is looking at this from a prior era here, and I think the General proves it. https://youtu.be/_up7IHd3LDs?t=218

The Air Force, feeling the budget squeeze, is rightfully concluding that the A-10 can go. They can perform the COIN/light ground attack role with much cheaper aircraft or by leveraging the huge advances in targeting with pods attached to the B-52, B-1, and F-15/F-16. At the high-threat end, they have the F-35, who's stealth, ECM, and sensors make it much more survivable than the A-10. (No, really. It does.)

And lastly, if anyone wants to see what this actually plays out like, try the A-10 simulator in DCS. It's a fantastic module. And then better yet, fly a mission or two on the public servers with the A-10 in a mixed threat environment. It'll be eyeopening.

And regarding those? I flew as part of a group online where we'd design and then fight realistic scenarios for our online wing. Props to our A-10 crews, but I got to see (simulated of course) just how limited these craft sometimes were. They were incredibly slow, and so took forever to get to the operational area, meaning the rest of our fighters had to either take off late, leaving them uncovered, or take off early and hit the tanker several times so that they'd be in the strike area to cover when they arrived. With a full load they were sitting ducks most of the time; jinking away from modern SAMs was practically impossible unless you were really sticking close to a ridgeline, which limited where you could go. Often the A-10s would get to the area after a long cruise, only to find some threats still up. They'd then have to loiter somewhere while an F/A-18 with HARMs came to clean up. We had a lot of aircraft overhead and around the A-10 to give it a role in the mission, whereas a package of 2-4 F-16s/F/A-18s with Mavericks could accomplish the same.

(Me? I flew the Viggen. We don't need no escorts, Swedish Dorito go "zoom".)

Anyways, hope this helps illustrate the issue for some of your detractors.